PT-2026-56505 · Honojs · Hono

Published 2026-07-08 · Updated 2026-07-08 · CVE-2026-59895

Mitre

CVSS v3.1

6.1

Medium

Base vector

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Hono is a Web application framework that provides support for any JavaScript runtime. From 4.0.0 before 4.12.27, cx() in hono/css composes class names from plain strings but marks the result as already escaped without HTML-escaping the input, allowing untrusted className values used in a JSX class attribute during server-side rendering to break out of the attribute and inject arbitrary markup. This issue is fixed in version 4.12.27.

Fix

Improper Encoding or Escaping of Output

XSS

Weakness Enumeration

CWE-116

CWE-79

Related Identifiers

CVE-2026-59895

Affected Products

Hono

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2026-59895 · Security Note
• https://github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fc · Note
• https://github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59 · Note
• https://github.com/honojs/hono/releases/tag/v4.12.27 · Note